1. Field of the Invention
The invention relates generally to a driving device, and more particularly to a driving device for controlling the rotation of a single phase motor.
2. Description of the Related Art
As various components inside computer systems consume more and more power, radiation heat correspondingly becomes more and more of an issue. An outstanding example can be seen when looking at the central processing unit (CPU). The older 386 CPU contains hundred thousands of transistor counts, while the newer Pentium 4 CPU contains more than 50 million transistor counts. The surface temperature of a common CPU may reach 50 to 80 degrees centigrade, and the inner temperature may reach 80 to 100 degrees centigrade. As such, various heat dissipation devices have been developed, and the most common is the use of a heat dissipating fan driven by a motor to remove heat.
The rotational speed of conventional heat dissipating fans is controlled by a driving current provided by motor control devices. Different driving currents drive the heat dissipating motor to rotate at different speeds in accordance with different levels of heat dissipation. It has become a main object for those with ordinary skill in the art to develop motor systems with efficient heat dissipating ability according to actual temperature status in electronics systems. The motor system would provide a precise driving current for control of suitable motor rotational speeds.